Add notification history; pin ecosystem crates to v0.7.2

Keep a bounded in-memory history (last 50) and a layer-shell window
listing app, summary, truncated body, and time. Toggle with
`breadbar --history` or D-Bus `dev.breadway.Bar.ToggleHistory`.

Pin bread-theme, bread-utils, and bread-screenshots to tag v0.7.2.
bread-shared stays on bread v0.8.0-rc.1.

README.md

@@ -33,6 +33,7 @@ A single Rust binary that provides a full-width top bar, a D-Bus notification da
 - Implements `org.freedesktop.Notifications` (D-Bus) — works with any standard sender (`notify-send`, etc.)
 - Popups appear top-right, stack vertically, auto-dismiss after the sender-specified timeout (default 5 s)
 - Supports `CloseNotification` and `replaces_id`
+- In-memory history of the last 50 notifications (app, summary, truncated body, time). Toggle with `breadbar --history` (Hyprland: `bind = SUPER, N, exec, breadbar --history`) or D-Bus `dev.breadway.Bar.ToggleHistory` on `org.freedesktop.Notifications` at `/dev/breadway/Bar`. Not persisted.
 
 **Volume/brightness OSD**:
 
@@ -138,8 +139,9 @@ Example — change the font size:
 | `src/bar/wifi.rs` | WiFi details popover, `breadcrumbs` profile/scan integration |
 | `src/bar/control.rs` | Control panel data: volume (`wpctl`), brightness (`brightnessctl`), sinks (`pactl`) |
 | `src/bar/tray.rs` | `org.kde.StatusNotifierWatcher` D-Bus service, SNI item rendering |
-| `src/notifications/mod.rs` | `org.freedesktop.Notifications` zbus service |
+| `src/notifications/mod.rs` | `org.freedesktop.Notifications` zbus service + `dev.breadway.Bar` history IPC |
 | `src/notifications/popup.rs` | Layer-shell popup window and card stack |
+| `src/notifications/history.rs` | Bounded in-memory history and layer-shell history window |
 | `src/osd.rs` | Volume/brightness on-screen display |
 | `src/widgets/` | Live Lua widgets from breadd (`BreadClient` + `WidgetSpec`) |
 | `src/theme.rs` | `bread-theme` palette loading, GTK CSS provider injection |